16th-Century Mapmaker's Intriguing Knowledge

Hessler said he thinks the phrases "now known" and "has been found to be" are crucial. They suggest geographical knowledge that is confirmed and believed, at least in some circles.

"The idea that this was a total guess is far-fetched," he said.

The people who knew were most likely Portuguese explorers (or at least sailed under the Portuguese flag). It was valuable, and most likely secret, knowledge. How it got to a priest-cartographer working under the patronage of the duke of Lorraine is a good question.

Equally intriguing is the shape of South America.

Inscribed along the western edge of that land mass in the 1507 map are the words "terra ultra incognita" -- land most unknown. But the border is not drawn as one long, ignorantly straight line. Instead, it is a series of straight lines meeting at shallow angles, implying a mixture of knowledge and uncertainty.

Using a technique called "polynomial warping," Hessler re-projected the image and compared Waldseemueller's continent with the real one.

There are many differences, of course. But the correlation is about 75 percent, and at two important places -- near the equator and near the place in northern Chile where the coast veers sharply to the northwest -- the width of Waldseemueller's South America and the actual one are almost the same.

Things were perhaps not as ultra incognita as he let on.

That is not the end of the strangeness, however.

In the large text block on the map, Waldseemueller requests "that those who are inexperienced and unacquainted with cosmography shall not condemn all this before they have learned what will surely be clearer to them later on, when they have come to understand it."

It is a plea. He knows his map is asking a lot.

In 1516, Waldseemueller published his second great map, called the Carta Marina. It shows South America no longer as an island. The continent disappears off the left of the page, implying it is attached to Asia, which is on the right edge.

Hessler has provided the first English translations of the second map's text blocks. In one of them, Waldseemueller says: "We will seem to you reader, to have diligently presented and shown a representation of the world previously, which was filled with error, wonder and confusion. . . . Our previous representation pleased very few people, as we have lately come to understand."

Was this a retraction? It sounds like it. Was a continental America heresy? Hessler said he has found no reason to think it was. So why would Waldseemueller change his new view of the world to an older one?

That's just one more mystery of the mysterious map.